Reversely bent retainer for pronged excavating tooth



June 6, 1967 G. A. PETERSEN 3,323,236

REVERSELY BENT RETAINER FOR PRONGED EXCAVATING TOOTH Filed June 1, 19652 Sheets-Sheet l INVENTOR. GERALD A. PETERSEN ATTORNEY REVERSELY BENTRETAINER FOR PRONGED EXCAVATING TOOTH Filed June 1, 1965 v 2SheGtS-Sheet 0L FIG- 6 INVENTOR. GER/4L0 A. PETERSEN A 7' TOPNE V UnitedStates Patent 3,323,236 REVERSELY BENT RETAINER FOR PRONGED EXCAVATINGTOOTH Gerald A. Petersen, Sunnyvale, Calif., assignor of one-half toAnita E. Petersen, Saratoga, Calif. Filed June 1, 1965, Ser. No. 460,0007 Claims. (Cl. 37142) This invention relates to a new and improvedreversely bent resilient retainer for pronged excavating tooth. Thisapplication comprises an improvement on Petersen Patent No. 2,968,880.The latter patent discloses an excavating tooth having a proximalportion formed with two longitudinal prongs defined by a slot extendingfrom top to bottom forwardly of the end of the tooth. The tooth holderhas forwardly-opening recesses to receive the prongs and resembles infront elevation the letter H turned on its side. The web between the topand bottom .flanges is complementary to the slot. In said patent, a

resilient retainer extends transversely through a hole in the web and iscompressed between the side walls of the slot and the contiguous wallsof the web. The present invention uses a resilient retainer which islocated and positioned in a different manner from that heretofore used.

Accordingly, the present invention has particular application to earthaugers, trenching machines, and the like, but is also adaptable tolarger earth-digging machines such as graders, clippers, back hoes,harrows, scarifiers, cable plows, and similar equipment Where a blade issubjected to heavier stresses than encountered in angers and trenchingmachines. The present invention enhances the area of surface contactbetween the resilient retainer and the surfaces between which it iscompressed and thus more securely holds the blade in its holder. Thus,the present invention holds the blade on its shank against unintentionaldislodgment despite extreme stresses tending to separate the parts. Onthe other hand, the retainer will permit intentional dislodgment of theblade holder when it is necessary to replace the blade.

It is a principal purpose of the present invention to provide means forretaining a blade on a permanent portion of a machine in such mannerthat it may be removed and sharpened, replaced, or otherwise repaired,and yet to provide a secure enough retention to prevent unintentionalseparation.

A particular advantage of the present invention is the facility withwhich the blade may be installed and removed and the fact that nospecial tools or other equipment are required for such purpose.

Still another advantage of the invention is the fact that the resilientinsert which secures the blade on its holder accommodates minorvariations in the construction of the blade and holder and thereby makesclose tolerances of dimensions of the mating parts unnecessary, andfurther accommodates wear of parts with passage of time.

As hereinafter described in detail, the resilient retainer is insertedin holes in the toothholder and the ends of the retainer extend into therecess in the holder and are positioned between the blade and the holderwhen the blade is forced into the holder. Grooves may be formed in theholder and the internal ends of the resilient retainer are compressedbetween the bottoms of the grooves and the adjacent wall of the blade.The cross-sectional shape of each groove is preferably substantiallydifferent from the initial unstressed shape of the resilient insert andhence there is a considerable deformation of the insert which increasesthe area of surface contact between the insert and the holder and theblade. Hence, the resistance to unidirectional dislodgment of the bladesfrom the holder is increased. When there is sufiicient clearance betweenblade and holder, use of grooves may be eliminated.

Another principal feature of the present invention is the fact thatneither bolts, metal keys, nor similar fasten ers, nor welding to securethe blade on the shank are used, thereby eliminating a considerableamount of the difficulty heretofore occasioned in securing blades totheir holders and removing the blades from the holders when required.

A distinguishing feature of one form of the invention hereinafterdescribed is the doubling over of the resilient retainer so that thereare two ends, both of which are compressed so as to retard separation ofthe parts, thereby materially increasing the resistance to withdrawal ofthe blades from the recess in the holder. A single retainer is bent in aU-shape and both of the ends are inserted through holes in thetoothholder wall, the metal between the holes serving to prevent theretainer from being pulled into the holder. The exterior wall of theholder may be recessed so that the bent over portion of the retainer isprotected against abrasion by being located below the exposed surface ofthe holder.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawingsin which similar characters of reference represent corresponding partsin each of the several views.

In the drawings:

FIG. Tis a top plan view partly broken away to conserve space of :atooth and holder in accordance with this invention.

FIGS. 2, 3, 4, and 5 are, respectively, sectional views taken alongcorresponding section lines in FIG. 1.

FIG. 6 is a view similar to FIG. 1 of a modification.

FIGS. 7, 8, and 9 are, respectively, sectional views taken alongcorresponding section lines in FIG. 6.

Tooth 11 shown in the accompanying drawings is similar to that toothshown in Petersen Patent No. 2,968,880. The distal end 12 has top andbottom downwardly-forwardly converging surfaces 13, 14, terminating in atruncated transverse end 16, and having generally parallel longitudinalvertical side edges 17. Said side edges 17 continue rearwardly toproximal side edges 18 of the proximal end 19 of said tooth. Therearward end 21 of the proximal portion has transverse vertical end 21and substantially parallel longitudinal top and bottom surfaces 22, 23.A rectangular slot is formed from top to bottom extendingforwardly-centrally from end 21, dividing the tooth into two proximalprongs 24, each substantially rectangular in cross-section defined byside edges 18, top and bottomsurfaces 22, 23, and the inwardly facingvertical walls 26 of the slot.

Toothholder 31 is attached by means forming no part of the presentinvention and not herein illustrated and described to a permanent orremovable part of the digging equipment. At its forward end, holder 31is shaped to receive the proximal prongs 24 of tooth 11 and for suchpurpose has top and bottom flanges 32, 33, and an interconnecting web34. Web 34 is dimensioned to fit within the slot of tooth 11 and thushas side wall 36 parallel to and in close proximity to walls 26 of thetooth. The top and bottom surfaces 37, 38, of flanges 32, 33, are spacedapart about the same distance as surfaces 22, 23, and are parallel toand in close proximity to said surfaces. Thus, when no retainer is used,the tooth 11 fits into and may be withdrawn from holder 31. A resilientretainer 41 is used to restrain unintentional dislodgment of the tooth.Retainer 41 may be formed of neoprene synthetic rubber, natural rubber,or other resilient material, such as nylon cord, latex-dipped nyloncord, soft iron wire, and other resilient substances. In theaccompanying drawings the cross-sectional shape of insert 41 in itsinitial dimension is circular but it will be understood that othershapes may be used. A distinguishing feature of the use of insert 41 isthat it is initially bent into a substantially U-shaped form prior toinsertion in the holder 31. To provide for such insertion, adjacent theforward end of holder 31 as in flange 32 a pair of downwardly-rearwardlydirected holes 42 is formed communicating with the recesses into \vyhichprongs 24 fit. A transverse arcuate groove 43 may beiormed in the topsurface of flange 32 so that insert 41 is recessed below the top surfaceand is protected againstabrasion. The inner ends 44 of insert 41 arecompressed lfetween surfaces 22 and 37. To accommodate such compressionwithout the necessity of unnecessarily large clearances-between surfaces22 and 37, grooves 46 may be formed in -surfaces 37. Preferably, grooves46 are thinner and broaderthan the corresponding dimensions of insert 41in its unstressed condition, thus spreading the ends 44 to the distortedshape best shown in FIG. 5,

\,au gmenting the area of surface contact with surface 22,

andincrea'sing the resistance to withdrawal of the teeth from itshol-der Although in FlGS'. ;1.-5, holes 42and groove 43 are shown formedin top flange iiz, it will be understood that they could be formed inbottom flange 33, and whereas the grooves 46 are shown in surface 37,nevertheless, they could be formed in surfaces 22 or 23.

In installing the tooth, insert 41 is bent into grmerally U-shape andthe ends 44 are inserted through holes 42h [insert resists withdrawal ofthe tooth from its holder and in normal usage unintentional withdrawalis prevented. However, when it is necessary to remove the tooth forsharpening, reversal or replacement, a tool may be inserted throughopenings 47 in holder 31 and driven against end 21 to force the toothforward against the resistance of the insert.

The modification of the invention shown in FIGS. 69 is similar to thatin the preceding modification and corresponding parts are designated bythe same reference numeral followed by the subscript a. However, in thisform of the invention holes 42a are located more closely together and infact are directly inwardly of walls 36 of web 34. Grooves 46a are formedin walls 36 and hence the ends 44a of insert 41a are compressed betweenthe bottoms of grooves 46a and web 34, and the inwardly facing walls 26aof prongs 24a.

Here again, it will be understood that although the holes 42a are formedin top flange 32a, they might also be formed in flanges 33a.

Here again, it will be understood that although the holes 4211 areformed in top flange 32a, they might also be formed in flanges 33a.

Whereas, a single insert 41 is shown in FIGS. 1 and 6, nevertheless aplurality of inserts may be used. For example, one insert might beinserted from the top and the other from the bottom. The inserts 41 and41a might both be used simultaneously so that the prongs 24a are engagedboth on a top or bottom surface and on an inwardly facing wall 26simultaneously. These modifications 4 readily will occur to one skilledin the art where problems of dislodgment of the tooth from its holderduring normal usage are unusually severe.

What is claimed is:

1. In earth digging equipment, a tooth having a distal portion and aproximal portion, said proximal portion divided into a pair of prongs bya slot extending forward from the proximal end of said tooth from top tobottom of said proximal portion, a tooth holder formed with forwardopening recesses to receive said prongs, and a web to fit within saidslot, said prongs having a pair of first surfaces, said recesses havinga pair of second surfaces in close proximity to said first surfaces,said holder formed with a pair of holes extending from the exterior ofsaid holder and communicating with said recesses, and a resilient insertdoubled over and having a pair of ends extending through said holes intosaid recesses and each positioned between a first and second wall torestrain unintentional withdrawal of said tooth from said holder.

2. The combination of claim 1, in which said second surface is locatedremoved from said web and said first surface is the contiguous surfaceof one of said prongs.

3. The combination of claim 1, in which said second surface is on saidweb and said first surfaceris-thewon tiguous surfac e ofoneofsaid'prongs'. A

4;The" combination of claim 1, in which said holder is formed with anexternal groove connecting the outer ends of said holes and theconnecting portion of said insert is received in said external groove. 7

5. The combination of claim 1, in which said second surfaces are formedwith longitudinal grooves rearward of the inner ends of said holes andthe inner ends of said insert are received in said longitudinal grooves.

6. The combination of claim 5, in which said longitudinal grooves areshallower and wider than the corresponding unstressed dimensions of saidinner ends of said insert.

7. In earth digging equipment, a tooth having a distal portion andproximal portion, said proximal portion having an extended firstsurface, a tooth holder formed with a forward opening recess to receivesaid proximal portion, said recess having an extended second surface inclose proximity to said first surface, said holder formed with a pair ofholes extending from the exterior of said holder and communicating withsaid recess at said second surface, and a resilient insert doubled overand having a pair of ends extending through said holes into said recess,each said end squeezed between said first and second surfaces torestrain unintentional withdrawal of said tooth from said holder.

References Cited UNITED STATES PATENTS 2,968,880 1/1961 Petersen 37-1423,057,091 10/1962 Petersen 37142 3,286,378 11/1966 Benetti 37-142ABRAHAM G. STONE, Primary Examiner.

R. CARTER, Assistant Examiner,

7. IN EARTH DIGGING EQUIPMENT, A TOOTH HAVING A DISTAL PORTION ANDPROXIMAL PORTION, SAID PROXIMAL PORTION HAVING AN EXTENDED FIRSTSURFACE, A TOOTH HOLDER FORMED WITH A FORWARD OPENING RECESS TO RECEIVESAID PROXIMAL PORTION, SAID RECESS HAVING AN EXTENDED SECOND SURFACE INCLOSE PROXIMITY TO SAID FIRST SURFACE, SAID HOLDER FORMED WITH A PAIR OFHOLES EXTENDING FROM THE EXTERIOR OF SAID HOLDER AND COMMUNICATING WITHSAID RECESS AT SAID SECOND SURFACE, AND A RESILIET INSERT DOUBLED OVERAND HAVING A PAIR OF END EXTENDING THROUGH SAID HOLES INTO SAID RECESSEACH SAID END SQUEEZED BETWEEN SAID FIRST AND SECOND SURFACES TORESTRAIN UNINTENTIONAL WITHDRAWAL OF SAID TOOTH FROM SAID HOLDER.